获取网站的基本网址，并在 Symfony 2中将其全局传递给 twig

Why do you need to get this root url ? Can't you generate directly absolute URL's ?

\{\{ url('_demo_hello', { 'name': 'Thomas' }) }}

This Twig code will generate the full http:// url to the _demo_hello route.

In fact, getting the base url of the website is only getting the full url of the homepage route :

\{\{ url('homepage') }}

(homepage, or whatever you call it in your routing file).

Instead of passing variable to template globally, you can define a base template and render the 'global part' in it. The base template can be inherited.

Example of rendering template From the symfony Documentation:

<div id="sidebar">
{% render "AcmeArticleBundle:Article:recentArticles" with {'max': 3} %}
</div>

Base url is defined inside Symfony\Component\Routing\RequestContext.

It can be fetched from controller like this:

$this->container->get('router')->getContext()->getBaseUrl()

This is now available for free in twig templates (tested on sf2 version 2.0.14)

\{\{ app.request.getBaseURL() }}

In later Symfony versions (tested on 2.5), try :

\{\{ app.request.getSchemeAndHttpHost() }}

You can use the new request method getSchemeAndHttpHost():

\{\{ app.request.getSchemeAndHttpHost() }}

 <base href="\{\{ app.request.getSchemeAndHttpHost() }}"/>

or from controller

$this->container->get('router')->getContext()->getSchemeAndHttpHost()

For Symfony 2.3+, to get the base url in a controller should be

$this->get('request')->getSchemeAndHttpHost();

\{\{ dump(app.request.server.get('DOCUMENT_ROOT')) }}

Valid from Symfony v2.1 through v6.0+

If you want the base URL to a Symfony application, you should use getSchemeAndHttpHost() concatenated together with getBaseUrl(), similar to how getUri() works, except without the router path and query string.

\{\{ app.request.schemeAndHttpHost ~ app.request.baseUrl }}

For example, if your Symfony website URL lives at https://www.stackoverflow.com/webapp/, then these two methods return these values:

getSchemeAndHttpHost

https://www.stackoverflow.com

getBaseUrl

/webapp

Note: getBaseUrl() includes the script filename (ie /app.php) if it's in your URL.

Also for js/css/image urls there's handy function asset()

<img src="\{\{ asset('image/logo.png') }}"/>

This creates an absolute url starting with /.

For current Symfony version (as of writing this answer it's Symfony 4.1) do not directly access the service container as done in some of the other answers.

Instead (unless you don't use the standard services configuration), inject the request object by type-hinting.

<?php


namespace App\Service;


use Symfony\Component\HttpFoundation\RequestStack;


/**
* The YourService class provides a method for retrieving the base URL.
*
* @package App\Service
*/
class YourService
{


/**
* @var string
*/
protected $baseUrl;


/**
* YourService constructor.
*
* @param \Symfony\Component\HttpFoundation\RequestStack $requestStack
*/
public function __construct(RequestStack $requestStack)
{
$this->baseUrl = $requestStack->getCurrentRequest()->getSchemeAndHttpHost();
}


/**
* Returns the current base URL.
*
* @return string
*/
public function getBaseUrl(): string
{
return $this->baseUrl;
}
}

See also official Symfony docs about how to retrieve the current request object.

In one situation involving a multi-domain application, app.request.getHttpHost helped me out. It returns something like example.com or subdomain.example.com (or example.com:8000 when the port is not standard). This was in Symfony 3.4.

I tried all the options here but they didnt work for me. Eventually I got it working using

\{\{ site.url }}

Hope this helps someone who is still struggling.

In Symfony 5 and in the common situation of a controller method use the injected Request object:

public function controllerFunction(Request $request, LoggerInterface $logger)
...
$scheme = $request->getSchemeAndHttpHost();
$logger->info('Domain is: ' . $scheme);
...
//prepare to render
$retarray = array(
...
'scheme' => $scheme,
...
);
return $this->render('Template.html.twig', $retarray);
}